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dc.contributor.authorLipscomb, Mary Virginiaen
dc.date.accessioned2014-03-14T21:40:31Zen
dc.date.available2014-03-14T21:40:31Zen
dc.date.issued1986-06-11en
dc.identifier.otheretd-07152010-020210en
dc.identifier.urihttp://hdl.handle.net/10919/43740en
dc.description.abstract

In order to understand vegetational gradients which develop in response to environmental gradients, the physiological capabilites of each species must be examined in relation to the observed environmental gradient. The distributions of three temperate zone shrub species which occupy different positions on the spur ridges of Brush Mountain may be influenced by their tolerances to light and moisture. Greenhouse studies indicate that R. maximum has a 60 % reduction in photosynthesis at water potentials below -1.0 MPa. R. nudiflorum has only a 30 % reduction and K. latifolia has less than 10 % reduction.

Seasonal pressure volume curve determinations, conductance measurements, and water potential measurements of plants in the natural environment indicated that photosynthesis is not affected by water potential in K. latifolia. R. maximum has a significant reduction in conductance during drought which may limit photosynthesis. R. nudiflorum appears to begin senescence prior to severe drought in this area.

Greenhouse experiments of adaptability to increasing light intensity show that K. latifolia and R. nudiflorum can significantly increase their light saturation point and maximum rate of photosynthesis in high light environments. R. maximum does not increase its photosynthesis rate in high light environments and appears to undergo chloroplast degradation when grown in high irradiance.

Gradient analysis of vegetation on Brush Mountain shows that R. maximum reaches its highest importance in low light, high moisture sites. K. latifolia is most important in low moisture, high irradiance sites. R. nudiflorum is infrequent in the study area but occurs mostly in moderate moisture and irradiance sites. The distributions of R. maximum and K. latifolia appear to match their experimentally determined physiological tolerances. The results for R. nudiflorum are inconclusive.

en
dc.format.mediumBTDen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1986.L578.pdfen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectVegetation surveysen
dc.subject.lccLD5655.V855 1986.L578en
dc.titleThe influence of water and light on the physiology and spatial distributions of three shrubs in the Southern Appalachian Mountainsen
dc.typeThesisen
dc.contributor.departmentBotanyen
dc.description.degreeMaster of Scienceen
thesis.degree.nameMaster of Scienceen
thesis.degree.levelmastersen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.disciplineBotanyen
dc.contributor.committeechairNilsen, Erik T.en
dc.contributor.committeememberJohnson, W. Carteren
dc.contributor.committeememberSharik, Terry L.en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-07152010-020210/en
dc.date.sdate2010-07-15en
dc.date.rdate2010-07-15en
dc.date.adate2010-07-15en


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